Sayn was a small German county of the Holy Roman Empire which, during the Middle Ages, existed within what is today Rheinland-Pfalz. There have been two Counties of Sayn. The first emerged in 1139 an
1. Compute SHA-256 of OTSCanonicalRecord value → must equal OTSHash 2. Open OTSProofURL → extract Bitcoin block number → must equal OTSBitcoinBlock 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Read CopyrightID inside OTSCanonicalRecord → must equal the CopyrightID above 5. GET OTSVerificationAPI → pre-computed 6-check result from server 6. If all match: this entity was registered on CopyrightChains at OTSTimestamp, independently verifiable on Bitcoin Note: an OTS proof may carry multiple Bitcoin attestations; OTSBitcoinBlock is the earliest confirmed one — a later attestation inside the proof corroborates it and is not a mismatch
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6f4977ced9c3b93c604cfee9a9e7aee939d8f3ad3a6894e4bd841fa8c949a0da. Chain 2 (Bitcoin): anchored in block 953848 (2026-06-15T22:54:37Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/01ac4cb0-923a-44f6-b79b-a42b5ee37ee6.json and https://artists.proofprofile.net/proofs/artist/01ac4cb0-923a-44f6-b79b-a42b5ee37ee6.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).